Takahiro Takazono

Correlation between triazole treatment history and susceptibility in clinically isolated Aspergillus fumigatus

ABSTRACT This is the first report of a detailed relationship between triazole treatment history and triazole MICs for 154 Aspergillus fumigatus clinical isolates. The duration of itraconazole dosage increased as the itraconazole MIC increased, and a positive correlation was observed (r = 0.5700, P < 0.0001). The number of itraconazole-naïve isolates dramatically decreased as the itraconazole MIC increased, particularly for MICs exceeding 2 μg/ml (0.5 μg/ml versus 2 μg/ml, P = 0.03). We also examined the relationship between cumulative itraconazole usage and the MICs of other azoles. A positive correlation existed between itraconazole dosage period and posaconazole MIC (r = 0.5237, P < 0.0001). The number of itraconazole-naïve isolates also decreased as the posaconazole MIC increased, particularly for MICs exceeding 0.5 μg/ml (0.25 μg/ml versus 0.5 μg/ml, P = 0.004). Conversely, the correlation coefficient obtained from the scattergram of itraconazole usage and voriconazole MICs was small (r = −0.2627, P = 0.001). Susceptibility to three triazole agents did not change as the duration of voriconazole exposure changed. In addition, we carried out detailed analysis, including microsatellite genotyping, for isolates obtained from patients infected with azole-resistant A. fumigatus. We confirmed the presence of acquired resistance to itraconazole and posaconazole due to a G54 substitution in the cyp51A gene for a patient with chronic pulmonary aspergillosis after oral itraconazole therapy. We should consider the possible appearance of azole-resistant A. fumigatus if itraconazole is used for extended periods.

Antifungal Susceptibilities of Aspergillus fumigatus Clinical Isolates Obtained in Nagasaki, Japan

ABSTRACT We investigated the triazole, amphotericin B, and micafungin susceptibilities of 196 A. fumigatus clinical isolates in Nagasaki, Japan. The percentages of non-wild-type (non-WT) isolates for which MICs of itraconazole, posaconazole, and voriconazole were above the ECV were 7.1%, 2.6%, and 4.1%, respectively. A G54 mutation in cyp51A was detected in 64.2% (9/14 isolates) and 100% (5/5 isolates) of non-WT isolates for itraconazole and posaconazole, respectively. Amphotericin B MICs of ≥2 μg/ml and micafungin minimum effective concentrations (MECs) of ≥16 μg/ml were recorded for two and one isolates, respectively.

Diagnostic significance of Aspergillus species isolated from respiratory samples in an adult pneumology ward.

Although the diagnostic significance of isolating Aspergillus spp. from respiratory cultures has been studied in immunocompromised hosts with invasive pulmonary aspergillosis (IPA), little is known of such infections in immunocompetent patients with other forms of aspergillosis. In this study of adult pneumology ward patients, we examined the association between Aspergillus spp. and disease prevalence. Laboratory records from April 1998 to March 2009 were reviewed to identify patients with Aspergillus spp. in respiratory samples. Correlations between the isolated species and clinical characteristics of patients were evaluated. During the study period, 165 Aspergillus spp. isolates were detected in the respiratory cultures of 139 patients. Of these patients, 62 (45%) were colonized with Aspergillus spp. and displayed no clinical symptoms of aspergillosis, while 77 (55%) had a form of pulmonary aspergillosis, characterized as either chronic necrotizing pulmonary aspergillosis (CNPA) (48%), aspergilloma (29%), IPA (13%), or allergic bronchopulmonary aspergillosis (ABPA) (10%). The dominant species were Aspergillus fumigatus (41%), A. niger (32%), and A. versicolor (12%). A. fumigatus was most commonly isolated in patients with IPA, aspergilloma, and CNPA, whereas A. niger was the dominant species in colonized patients and those with ABPA. Isolation of an Aspergillus spp. from respiratory samples does not confirm it as the etiologic pathogen because airway colonization by Aspergillus spp. is a common feature in several chronic lung diseases. Repeated isolation of the identical Aspergillus species and detection of anti-Aspergillus antibodies and/or Aspergillus antigens in sera are needed to determine the isolate represents the etiologic agent of disease.

Clinical features, risk factors and treatment of fulminant Mycoplasma pneumoniae pneumonia: A review of the Japanese literature

Mycoplasma pneumoniae (MP) is one of the most common causes of community-acquired pneumonia in children and young adults. Although MP sometimes causes self-limiting pneumonia, severe and fulminant cases with hypoxia occur, but their clinical features have rarely been reported. This study aimed to reveal the clinical manifestations, risk factors, and treatment of fulminant MP pneumonia (MPP). Using PubMed and abstracts from the proceedings of several domestic Japanese academic societies, we reviewed the Japanese and English literature for cases of fulminant or severe MPP reported in Japan. All clinical information such as sex, age, underlying diseases, clinical symptoms, clinical course, laboratory and radiological findings, and treatment was collected and analyzed. In total, 52 fulminant MPP cases were reported between September, 1979 and February, 2010. The dominant population of fulminant MPP was young adults without severe underlying diseases. Cough (97.3%), fever (100.0%), and dyspnea (83.3%) with diffuse abnormal findings in radiological examinations were noted. Antibiotics without anti-mycoplasmal activity were used in 32 cases (61.5%) as initial treatment prior to the onset of hypoxia. Anti-mycoplasmal drugs were appropriately used in 41 cases (78.8%) after onset of respiratory failure with steroids (23 cases, 45.1%) and effective. The majority of patients improved within 3-5 days after steroid administration. There were only 2 fatal cases. Although this small retrospective study did not reveal the apparent risk factors of fulminant MPP, initial inappropriate use of antibiotics may be a risk factor, and early administration of appropriate anti-mycoplasmal drugs with steroids as a cellular immune suppressor is required.

Multilocus sequence typing of Cryptococcus neoformans in non-HIV associated cryptococcosis in Nagasaki, Japan

Cryptococcosis is primarily caused by two Cryptococcus species, i.e., Cryptococcus neoformans and C. gattii. Both include several genetically diverse subgroups that can be differentiated using various molecular strain typing methods. Since little is known about the molecular epidemiology of the C. neoformans/C. gattii species complex in Japan, we conducted a molecular epidemiological analysis of 35 C. neoformans isolates from non-HIV patients in Nagasaki, Japan and 10 environmental isolates from Thailand. All were analyzed using URA5-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Combined sequence data for all isolates were evaluated with the neighbor-joining method. All were found to be serotype A and mating type MATα. Thirty-two of the 35 clinical isolates molecular type VNI, while the three remaining isolates were VNII as determined through the URA5-RFLP method. Thirty-one of the VNI isolates were identified as MLST sequence type (ST) 5, the remaining one was ST 32 and the three VNII isolates were found to be ST 43. All the environmental isolates were identified as molecular type VNI (four MLST ST 5 and six ST 4). Our study shows that C. neoformans isolates in Nagasaki are genetically homogeneous, with most of the isolates being ST 5.

Skn7p is involved in oxidative stress response and virulence of Candida glabrata.

Candida glabrata is an opportunistic fungal pathogen that causes both superficial and deep-seated mycosis in humans. In Saccharomyces cerevisiae and several pathogenic fungi, Skn7p is known as a transcriptional factor involved in oxidative stress response (OSR) but functions of its ortholog have been little investigated in C. glabrata. In this study, we constructed a C. glabrataskn7 deletion strain by the ura-blaster technique and investigated mutant phenotypes related to OSR and virulence. The C. glabrataskn7 deletant showed increased susceptibility to hydrogen peroxide and tert-butyl hydroperoxide. Our transcriptional assay evaluated by quantitative real-time PCR revealed that, in response to the treatment with hydrogen peroxide, transcription of some putative Skn7p target genes including TRX2, TRR1, TSA1 and CTA1 were not fully induced in the skn7 deletant compared to the wild-type control, consistent with the susceptibility phenotype. Furthermore, the deletion of SKN7 resulted in attenuated virulence in a murine model of disseminated candidiasis. These results suggest that Skn7p may play a role in transcriptional regulation of its target genes required for OSR and virulence in C. glabrata.

Bronchoalveolar lavage galactomannan for the diagnosis of chronic pulmonary aspergillosis

Diagnosing chronic pulmonary aspergillosis (CPA) is complicated, and there are limited data available regarding the identification of galactomannan (GM) in clinical specimens to assist the detection of this infection. The purpose of this study was to evaluate the detection of GM in bronchoalveolar lavage fluid (BALF) and serum and to assess its utility for diagnosing CPA. We retrospectively reviewed the diagnostic and clinical characteristics of 144 patients, with and without CPA, in Nagasaki University Hospital, Japan, whose BAL and serum specimens were examined for the presence of GM. The Platelia Aspergillus enzyme immunoassay (PA EIA) was performed according to the manufacturers instructions. The mean values of BALF GM antigen were 4.535 (range, 0.062-14.120) and 0.430 (range, 0.062-9.285) in CPA (18) and non-CPA (126) patients, respectively. The mean values of serum GM antigen were 1.557 (range, 0.232-5.397) and 0.864 (range, 0.028-8.956) in CPA and non-CPA patients, respectively. PA EIA of BALF is superior to the test with serum, with the optimal cut-off values for BALF and serum of 0.4 and 0.7, respectively. The sensitivity and specificity of PA EIA in BALF at a cut-off of 0.4 were 77.2% and 77.0%, respectively, whereas with serum at a cut-off of 0.7, they were 66.7% and 63.5%, respectively. GM testing using BALF showed reasonable sensitivity and specificity as compared to that using serum. Thus, assessing GM levels in BALF may enhance the accuracy of diagnosing CPA.

The risk factors for developing of chronic pulmonary aspergillosis in nontuberculous mycobacteria patients and clinical characteristics and outcomes in chronic pulmonary aspergillosis patients coinfected with nontuberculous mycobacteria

Patients with chronic pulmonary aspergillosis (CPA) have a poor prognosis and CPA occurs in patients with various underlying diseases. Recently, the number of patients with CPA complicated by nontuberculous mycobacteria (NTM) has increased. Additionally, complications of both diseases have several problems like drug interactions. Since the impact of NTM on the outcome of CPA is not well understood, we investigated the risk factors for developing CPA and the clinical characteristics of CPA patients with or without NTM. We retrospectively investigated the medical records of NTM and CPA patients who were admitted to Nagasaki University Hospital between April 2008 and September 2013. Comorbid diseases, causative microorganisms, radiological findings, and outcomes were evaluated. During the study period, 82 and 41 patients were diagnosed as having NTM and CPA, respectively. Nine patients were coinfected with NTM and CPA, and cavitary type NTM and steroid usage were independent risk factors of development of CPA. Mortality rates in the coinfection group were significantly higher than those of the NTM without CPA group (P = .003, log-rank test). The rate of treatment initiation in the co-infection group (33.3%) was significantly lower than in the CPA without NTM group (84.4%) (P = .006). However, there were no significant differences in cumulative survival rate between both groups (P = .760, log-rank test). Cavity formation and steroid usage were the independent risk factors for NTM patients to develop CPA within long observation period, and development of CPA made outcomes poor. It is important to diagnose the development of CPA early and initiate treatment for CPA.

A case of bronchial aspergillosis caused by Aspergillus udagawae and its mycological features

Aspergillus udagawae and A. fumigatus share similar morphological features but they differ genetically. There is also an important clinical distinction as A. udagawae is less sensitive to amphotericin B than A. fumigatus. We encountered a rare case of bronchial infection due to A. udagawae that was successfully treated with voriconazole. An 82-year-old woman with diabetes mellitus complained of bloody sputum. Bronchoscopy revealed a white plugged region at the origin of the right bronchi B5. Cytological study revealed a clot composed of filamentous fungi and Aspergillus spp. was detected by culture. Molecular analysis revealed that the causative agent was A. udagawae, and voriconazole was used for the treatment. In comparison to A. fumigatus, the A. udagawae strain isolated in this case was less sensitive to amphotericin B, less virulent in immunosuppressed mice, and more sensitive to hydrogen peroxide, features that are almost identical to those of the previously reported isolates of the fungus. We should be aware of the emergence of new Aspergillus species that might pose a clinical threat.

Efficacy of Combination Antifungal Therapy with Intraperitoneally Administered Micafungin and Aerosolized Liposomal Amphotericin B against Murine Invasive Pulmonary Aspergillosis

ABSTRACT Targeted intrapulmonary delivery of drugs may reduce systemic toxicity and improve treatment efficacy. In the current study, we evaluated the effects of a combination treatment consisting of inhalation of aerosolized liposomal amphotericin B (L-AMB) with intraperitoneal administration of micafungin (MCFG) against murine invasive pulmonary aspergillosis. The combination of aerosolized L-AMB with intraperitoneal MCFG significantly improved the survival rate, and the fungal burdens and histopathology findings after this treatment were superior to those of the control and both monotherapy groups.